How can I Get the members of an existing group repository and Add members to a existing group repository.

How can I modify additional properties of a repository. Like:
- Online status
- Adding a clean-up policy to the repo
- Additional remote storage properties of a proxy repo (Check the screenshot attached)

How to configure the security part, I need to implement below tasks:
- add content selectors
- add custom privileges using the content selectors
- add custom roles adding the privileges : guess the addRole() function covers this. > Does this role sync with the a LDAP role?
- add additional privileges or roles to an existing role
- delete content selectors, privileges and roles